1. Field of the Invention
The present invention relates to a honeycomb structural body, more particularly a honeycomb structural body to be used as a filter for removing fine particles, a substrate for catalysts in a catalytic converter for purifying exhaust gases emitted from an internal combustion engine, or a substrate for catalysts in a catalytic converter for purifying and/or deodorizing burnt gases of petroleum oils, and a method of producing the same.
2. Related Art Statement
Heretofore, in order to withstand violent vibrations during use, catalytic converters which are mounted on automobiles include generally, as shown in FIG. 4, a supporting system wherein a honeycomb structural body is supported not only by supporting members 12-1, 12-2 (to be referred to as "cushioning member", hereinafter) having a cushioning property in a direction orthogonal (to be referred to as "radial direction", hereinafter) to a direction of throughholes 11-1, 11-2 through which an exhaust gas is flowed, but also by positioning and supporting plates 13-1, 13-2 directly or via a cushioning member 12-1 in the direction of the throughholes. However, in such a supporting system, the throughholes 11-2 of the honeycomb structural body are abutted and closed by a portion of the cushioning member 12-1, so that the closed throughholes of the honeycomb structural body are vainly left unused. Therefore, in order to save expensive noble metals of the catalyst at such unused throughholes, a supporting system using only a sealing member 14 as shown in FIG. 5, having a cushioning or buffering property (to be referred to as "sealing member", hereinafter), such as a ceramic mat, etc., around the whole side surface or circumferential surface of the honeycomb structural body, and supporting the honeycomb structural body solely in radial directions by the sealing member 14 is also practiced in the field of the art.
Also, a supporting system is known, as disclosed in Japanese Utility Model Application Laid-open No. 62-179,319, wherein, in order to prevent scattering of the sealing member, a barrier is formed on the outer circumferential surface of the ceramic honeycomb structural body at a location adjacent to at least one end surface of the sealing member.
The above described practiced system of supporting the honeycomb structural body only in radial directions thereof has to exert a high pressure on the honeycomb structural body in radial directions, in order to prevent displacement of the honeycomb structural body in the supporting system of catalytic converters due to violent vibrations during use. Therefore, the supporting system can support the honeycomb structural body in radial directions thereof, only when the honeycomb structural body has so relatively thick partition wall thickness of, for example, 0.3 mm in thickness so that it can exhibit a high strength to withstand an exerted high exterior supporting pressure. However, the supporting system has a drawback in that it can not be practiced, if the honeycomb structural body has relatively thin partition walls of, for example, 0.15-0.20 mm in thickness so, that it has an insufficient low strength to withstand an exerted high exterior supporting pressure.
Also, the technique of Japanese Patent Application Laid-open No. 62-179,319 has a drawback in that it is wholly useless in preventing a displacement of the honeycomb structural body in circumferential directions, namely, a rotation thereof.